The Time Ring takes the Doctor, Sarah, and Harry back to the Nerva Colony, but thousands of years early. The station is being used as a beacon to warn space traffic of a new asteroid orbiting Jupiter. This is Voga, or the Planet of Gold. The time-travellers learn that a space-plague has killed most of Nerva’s crew. A scientist named Kellman (Jeremy Wilkin) is a traitor working with the Cybermen, who want to destroy Voga as they can be killed with gold-dust.
The plague is caused by poison injected into its victims by Cybermats—small crawling creatures related to Cybermen. The Cybermen invade the station and force the Doctor and two humans to transport cobalt bombs to the center of the asteroid. Kellman is a double agent, secretly working with one faction of the Vogans. Their plan is to lure the Cybermen onto the station and destroy it with a rocket called the Skystriker. The Doctor gets rid of the cobalt bomb and returns to the station, which the Cybermen evacuate when they learn of the imminent Vogan attack.
The missile is launched, but the Doctor directs it to the Cybermen’s ship. All this time, the TARDIS has been drifting back in time to rendezvous with the time travellers (called by the Time-Ring), who leave for Earth to answer a call from the Brigadier.
Voga is an island of gold that Columbus hoped to find in the Atlantic. The Vogans are not to be confused with the Vogons of Hitch-hiker’s Guide to the Galaxy, who are the worst poets in the universe. The story did not get much respect. It was thought to be good characters trapped in a poor plot, and the Cybermen were accused of showing too much emotion. Even the title was criticized. Revenge of the Cybermen makes even less sense than Revenge of the Jedi. The interior of the asteroid was played by the Wookey Hole Caves in Somerset, which was supposed to be cursed. The crew put a witch’s hat and cloak on a rock formation called The Witch. Four people were injured, sickened, or involved in accidents, including Elizabeth Sladen, whose boat went crazy and headed for a waterfall. She had to jump in the water to save herself; she and a stuntman who jumped in after her got an infection. The boat was never found. The radio transmitter disguised as a clothes brush came from Live and Let Die, purchased from Roger Moore himself.